The Sigma 20mm 1.4 DG HSM Art is a state of the art wide-angle prime lens designed for Full Frame cameras but will work with APS-C sensors as well. Using over 50 years of lens making experience, particularly the knowledge gained from the 35mm 1.4 Art and the 24mm 1.4 Art, the 20mm 1.4 Art is the widest large aperture Art lens to date. The latest optical design allows for the utmost in image quality with careful attention paid to edge to edge performance. Through decades of experience in lens design and Sigma Global Vision lens manufacturing, the 20mm incorporates both "F" Low Dispersion (FLD) glass, and five Special Low Dispersion (SLD) glass in a design of 15 elements in 11 groups. The combination of advanced optics and optimized lens power distribution minimizes spherical aberration, axial chromatic aberration and field curvature, producing outstanding image quality. With class leading performance, this lens is ideal for landscape photography, videography, astrophotography, lowlight/indoor photography and event photography. As with all Global Vision lines, the 20mm will be tested using the proprietary "A1" measuring system ensuring the highest standard of operation. The Sigma 20mm Art is compatible with the USB dock to update and customize and is also compatible with the Mount Conversion Service. A staple procedure for the Global Vision lines, every lens will be tested using the proprietary "A1" measuring system.

With a focal length of 20mm and F1.4 aperture, this lens delivers outstanding large-aperture brightness and bokeh, delivering unprecedented visual experiences.SIGMA has extensive experience in leveraging its advanced design capabilities and leading-edge technologies to craft large-aperture prime lenses that bring out the full potential of ultra-high-megapixel DSLRs. As its latest achievement in this category, SIGMA has created an ultra-wide-angle lens with F1.4 brightness. With a focal length of 20mm and F1.4 aperture, this lens delivers outstanding large-aperture brightness and bokeh, delivering unprecedented visual experiences. Allowing the photographer to leverage the perspective provided by the wide -angle and the shallow depth of field provided by the large aperture, this lens is ideal not only for such ultra-wide-angle subjects as landscapes and starry skies, but also for snapshots in low light, indoor photography, portraits with a natural bokeh effect, and much more.

Art line delivers high-level artistic expressionSIGMA is organizing all its interchangeable lenses into three product lines: Contemporary, Art, and Sports, each with a distinctive concept. Designed with a focus on sophisticated optical performance and abundant expressive power, our Art line lenses deliver high-level artistic expression. Offering astonishing rendering performance that meets the highest standard, they are perfect for landscapes, portraits, still-lifes, close-ups, and casual snaps. They are made for the kind of photography that unleashes the inner artist. A powerful ally in every genre of photography, SIGMA's Art line lenses excel both in the studio for formal works and outdoors for impressive shots of architecture, starry skies, and many other scenes.

Advanced technologies make a 20mm F1.4 lens possibleWorld's first 20mm F1.4 lens-thanks to advanced large-diameter aspherical lens manufacturing technologiesTo offer an ultra-wide-angle 20mm focal length and F1.4 brightness at wide-open aperture, this lens incorporates a large double aspherical lens 59mm in diameter. Lenses of this type had been considered extremely difficult to manufacture, but SIGMA took on the challenge to realize an F1.4 ultra-wide-angle lens that fulfills the strict performance requirements of the SIGMA Art line. What made this breakthrough possible were SIGMA's advanced manufacturing technologies, which the company has developed over time by producing a wide range of ultra-wide-angle and large-aperture lenses. For example, milestone lenses such as SIGMA 12-24mm F4.5-5.6 EX DG ASPHERICAL HSM, SIGMA 8-16mm F4.5-5.6 DC HSM, and SIGMA 18-35mm F1.8 DC HSM | Art were completely original products that helped SIGMA develop outstanding design and production know-how and its current high-precision, high-efficiency production system. In turn, these advances made possible the new SIGMA 20mm F1.4 DG HSM | Art. Moreover, SIGMA's advanced optical design minimizes distortion, transverse chromatic aberration, sagittal coma flare, and the reduction of brightness toward the edges of the image. Delivering top performance even at wide-open aperture, this lens can be considered the culmination of SIGMA's Art line.

Minimized chromatic aberrationsThis lens minimizes chromatic aberrations, a common issue in large-aperture ultra-wide-angle lenses. It features two FLD ("F" Low Dispersion)* glass and five SLD (Special Low Dispersion) glass elements to minimize transverse chromatic aberration, which is mainly visible around the edge of the image. The optimized lens power distribution helps minimize axial chromatic aberration. As a result, this lens delivers high image quality in every situation without color smearing, and its rendering performance is consistently sharp with high contrast.

* FLD glass is ultra-low-dispersion glass that offers performance of the highest level. Highly transparent, its refractive index and dispersion are extremely low as compared to conventional types of glass. It offers characteristics very similar to those of fluorite, which is valued for its high anomalous dispersion. These characteristics minimize residual chromatic aberration (secondary spectrum), which cannot be corrected by ordinary optical glass, while helping to produce sharp, high-contrast images.

Minimized distortionDistortion is a common issue in wide-angle lenses, and it is not possible to correct it simply by changing the aperture value. For this reason, a lens must be designed from the start to minimize this issue. By adjusting the incidence angle of light starting with the first lens element and incorporating optimally positioned aspherical glass elements, the SIGMA 20mm F1.4 DG HSM | Art lens minimizes distortion throughout the entire image.

Exclusive low-dispersion glassThe degree to which light is refracted by glass depends on the light's wavelength. This fact causes different colors of light to focus at slightly different points. The result is chromatic aberration, the color fringing that is particularly noticeable in telephoto lenses. Most chromatic aberration can be removed by combining a high-refractivity convex lens element with a low-refractivity concave element. Yet residual chromatic aberration known as "secondary spectrum" may still remain. To minimize this secondary spectrum, which can be a serious issue with conventional lenses, SIGMA lenses feature up to three types of exclusive low-dispersion glass offering superior performance: ELD (Extraordinary Low Dispersion), SLD (Special Low Dispersion) and FLD ("F" Low Dispersion). In particular, FLD glass offers ultra-low dispersion in combination with high transmittance and the anomalous dispersion characteristics of fluorite. Meticulous deployment of these types of exclusive low-dispersion glass and optimization of power distribution gives SIGMA lenses superlative image rendition undiminished by residual chromatic aberration.

Flare and ghosting reductionFrom an early stage in the lens design process, flare and ghosting have been measured to establish an optical design resistant to strong incident light sources such as backlighting. SIGMA's Super Multi-Layer Coating reduces flare and ghosting to help photographers produce sharp and high contrast images even in backlit conditions.

The ideal high-speed lens for snapshots and much moreTop-level performance for the ultra-high-megapixel eraAt the dawn of the film camera, there was very little high-sensitivity film, and bright lenses that worked well in low-light conditions came to be known as "high-speed lenses." These lenses are ideal for shooting indoors, in the evening, under cloudy skies, or in any low-light situation. Since the SIGMA 20mm F1.4 DG HSM | Art provides the benefits of an ultra-wide angle lens with minimal distortion, it is ideal for photographing landscapes, starry skies, and architecture. In addition to capturing wide-angle shots with the whole scene in focus, the photographer can leverage wide-open aperture to take snapshots with the subject in focus and the background blurred with an attractive bokeh effect. Designed for ultra-high-megapixel digital cameras, this high-performance lens delivers outstanding resolution and high-clarity image quality even at wide-open aperture.

The finest in materials, usability and functionality.A refined, integrated design made with the photographer in mindIn our new product lines, the lens caps and AF/MF switches are newly designed to improve usability. To ensure precise operation, internal parts feature generous use of metal and Thermally Stable Composite (TSC)*, which is highly compatible with metal parts. The lens barrel is engraved with the year of release for instant access to this information.

* TSC offers thermal expansion characteristics similar to those of aluminum. Parts made with TSC deform less, making lens construction of extremely high precision possible. As compared to polycarbonate containing 20% glass, a commonly used material, TSC offers approximately 70% higher elasticity. As compared to polycarbonate containing 30% glass, it offers 25% higher elasticity. (Comparison is between SIGMA-produced components.)

Hyper Sonic Motor ensures high AF speedThe Hyper Sonic Motor (HSM) ensures silent, high-speed autofocusing, while the optimized AF algorithm helps realize even smoother AF performance. At any time during AF, users may access MF simply by rotating the focus ring. This feature makes faster focus adjustment possible, since there is no need to use the AF/MF focus mode switch. Also, the optional SIGMA USB DOCK allows the user to set the lens to conventional full-time manual focus override. Note: The operation of full-time MF may vary based on mount type.

Rounded diaphragmThe 9-blade rounded diaphragm creates an attractive blur in the out-of-focus areas of the image.

Metal lens cap available (sold separately)Matching the high-quality finish of the lens exterior, optionally available metal lens cap LC907-02 will go on sale simultaneously with the lens. Featuring materials identical to those of the lens barrel, this metal lens cap establishes a new level of unity within SIGMA's new lens lines.

SIGMA USB DOCK makes customization and flexible adjustment possibleSIGMA USB DOCK for SIGMA GLOBAL VISION lenses (optional)With the optional SIGMA USB DOCK, you can update your lens firmware and adjust the focus position and other settings. Simply connect the lens to the SIGMA USB DOCK and the dock to a computer to use the dedicated SIGMA Optimization Pro software and perform various types of customization and adjustment.

New SIGMA GLOBAL VISION product lines are setting new benchmarks for image qualityEvaluation with SIGMA's own MTF measuring system: A1 used to measure lens performance with a Modulation Transfer Function (MTF) measuring system using conventional sensors. However, Sigma has developed their own proprietary MTF measuring system (A1) using 46-megapixel Foveon direct image sensors. Even previously undetectable high-frequency details are now within the scope of quality control inspections. All SIGMA 20mm F1.4 DG HSM | Art lenses are checked using this A1 system before they are shipped.

46-megapixel Foveon direct image sensorThe 46 effective megapixel (4,800 X 3,200 X 3 layers) and 44 recording megapixel (4,704 X 3,136 X 3 layers) 23.5 X 15.7mm APS-C X3 direct image sensor captures all primary RGB colors at each and every pixel location, ensuring the capture of full and complete color. Using three silicon-embedded layers of photo detectors, stacked vertically to take advantage of silicon's ability to absorb red, green and blue light at different respective depths, it efficiently reproduces color more accurately, and offers sharper resolution, pixel for pixel, than any conventional image sensor. Since color moire is not generated, the use of a low-pass filter is not required, meaning light and color, generated by the 46-megapixel APS-C X3 direct image sensor is captured with a three-dimensional feel.

Available for Sigma's Mount Conversion Service that enables lenses to be long term assets (charges apply)Continue using your favorite lens with a different camera body.Over the years, SIGMA has manufactured an extremely wide variety of interchangeable lenses. Leveraging their unique know-how and resources, Sigma's new Mount Conversion Service, which will be available for the SIGMA 20mm F1.4 DG HSM | Art and other SIGMA interchangeable lenses SIGMA will convert the current lens mount internal components, allowing you to continue using your favorite SIGMA lenses from the new product lines with a different camera body. Thanks to this service, you can use a favorite lens for many years to come, unrestricted by your original choice of camera system.Note: SIGMA's mount conversion service differs from ordinary repairs and product support and is not offered at your local SIGMA dealer or camera store. To access this service, please communicate directly with SIGMA.

Ultra-high precision and quality-all made in Japan.With only a few minor exceptions, all of SIGMA's manufacturing, including molds and parts, takes place under a single integrated production system in Japan. Sigma is now one of the very few manufacturers whose products are truly made in Japan. Sigma likes to think their products are somehow imbued with the essence of their homeland, blessed as it is with clean air and water, and focused, hard-working people. Sigma prides themselves on the authentic quality of SIGMA products, born of a marriage between highly attuned expertise and intelligent, advanced technology. Their sophisticated products have satisfied professionals and lovers of photography all over the world because their manufacturing is based on genuine craftsmanship, underpinned by the passion and pride of their experts.